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Grade 12Algebra

Let R be the set of real numbers, f : R?R be the function defined by f (x) = 4x + 3, x ? R. Show that f is invertible. Find the inverse of f ?

Profile image of sudhanshu
12 Years agoGrade 12
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1 Answer

Profile image of Jitender Singh
12 Years ago
Ans:
f : R\rightarrow R
f(x) = 4x + 3
Since range of function is equal to co-domain, so it is onto function.
It is straight line, so it is clear from the graph that it is one to one function.
-> f(x) is bijective function, so it can be invertible.
x\rightarrow f^{-1}(x)
f(f^{-1}(x)) = 4f^{-1}(x) + 3
f(f^{-1}(x)) = x
f^{-1}(x) = \frac{x-3}{4}
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Jitender Singh
IIT Delhi
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